JP7482339B1 - Receiving substrate, laser lift-off method, lifting method, holding method, and method for cleaning microstructure - Google Patents

Abstract

The present invention provides a receiving substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off, the receiving substrate having a curable resin layer on the surface onto which the microstructure is transferred, thereby providing a receiving substrate that can receive the microstructure while suppressing damage, and can hold the microstructure while suppressing misalignment and tilt.

Description

The present invention relates to a receiving substrate used when transferring microstructures such as mini light-emitting diodes (hereinafter also referred to as mini LEDs) and micro light-emitting diodes (hereinafter also referred to as micro LEDs) and a manufacturing method for the receiving substrate, a laser-induced forward transfer (LIFT) method for transferring the microstructures, a holding method for holding the microstructures on the receiving substrate, and a method for cleaning the microstructures.

In recent years, as semiconductor elements have become smaller, attention has been focused on microstructure transfer technology using adhesive resins as a means of assembling electrical and electronic products using semiconductor elements. In particular, there has been active development of technology to manufacture LED displays for use in signage, TVs, medical applications, in-vehicle displays, smartphones, and other applications by transferring tens of thousands of mini-LEDs (LED elements with short sides of 100 μm or more to several hundred μm) or micro-LEDs (LED elements with short sides of 100 μm or less, or even 50 μm or less) at once.

Previously, we have developed a method for transferring microstructures such as micro LEDs and mounting them on a circuit board using silicone adhesive cured materials as donor substrates and transfer stamp materials (Patent Document 1).

On the other hand, as a method for electrically connecting a transferred microstructure such as an LED element to a circuit board, a method is known in which solder particles (hereinafter also referred to as bumps) are applied to the electrodes of the microstructure, and the microstructure is mounted on the wiring of the circuit board, and then reflow is performed to melt the solder components contained in the bumps and make them conductive. When transferring a microstructure containing such a bump, the bumps are often rounded in shape, so that the mounting position on the donor plate is not uniform, and there is a problem that the bumps are tilted relative to the plate plane. In addition, for example, after laser lift-off (hereinafter also referred to as LLO) of a blue LED element, Ga adheres to the surface of the microstructure. If a hydrochloric acid solution is used as a cleaning solution to remove this, the solder components dissolve at the same time, changing the composition, and the melting point during reflow increases, causing a problem that affects the next process. In addition, the microstructures often fall off due to the impact during cleaning.

JP 2021-34610 A

The present invention has been made to solve the above problems, and aims to provide a receiving substrate that can receive a microstructure while minimizing damage and can hold the microstructure while minimizing misalignment and tilt, a method for manufacturing such a receiving substrate, a lifting method that can transfer a microstructure from a supply substrate to a receiving substrate while minimizing damage and hold the microstructure while minimizing misalignment and tilt, a holding method that can minimize misalignment and tilt of the microstructure, and a cleaning method that can clean the microstructure while minimizing falling off, misalignment and tilt.

In order to solve the above problems, the present invention provides a receiving substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off, comprising:
A receiving substrate having a curable resin layer on the surface to which the microstructure is transferred is provided.

The receiving substrate of the present invention can prevent localized stress from being applied to the microstructure during laser lift-off (LLO) and can firmly hold the microstructure. Therefore, the receiving substrate of the present invention can receive the microstructure while minimizing damage, and can also hold the microstructure while minimizing misalignment and tilt.

For example, the curable resin layer is photocurable or thermocurable.

The curable resin layer is not particularly limited as long as it is curable, but may be, for example, photocurable or thermocurable.

For example, the curable resin layer may be in B-stage.

The curable resin layer may be in a B-stage, i.e. semi-cured state. After receiving the microstructure, such a resin layer can be subjected to a secondary curing process to hold the microstructure without causing misalignment or tilting.

The curable resin layer is preferably in a gel state.

A gel-like resin layer can more reliably prevent damage to the microstructure during laser lift-off.

For example, the curable resin layer may be a silicone-based gel layer.

The curable resin layer is not limited to, but can be, for example, a silicone-based gel layer.

It is preferable that the curable resin layer has tackiness to the microstructure.

Such a resin layer can further prevent the received microstructure from shifting out of position.

It is preferable that the hardness of the curable resin layer increases upon curing.

If the resin layer becomes harder as it hardens, the positional shift or tilt of the microstructure can be further reduced after hardening.

Alternatively, it is also preferable that the curable resin layer increases its adhesive strength to the microstructure or increases its retention strength of the microstructure upon curing.

With such a resin layer, misalignment and tilt of the microstructure can be more reliably suppressed after hardening.

Alternatively, it is also preferable that the curable resin layer becomes rubber-like when cured.

If the resin layer becomes rubber-like when hardened, the positional shift and tilt of the microstructure can be further reduced after hardening.

In this case, for example, the storage modulus of the curable resin layer may be 10 to 1000 Pa at 25°C, and may become 1 MPa to 30 GPa upon curing.

The curable resin layer may, for example, be one in which the storage modulus increases upon curing in this manner.

The present invention also provides a method for producing a receiving substrate having a curable resin layer, the method comprising the steps of: forming a layer of a resin capable of at least two types of curing reactions on one side of a substrate for preparing a receiving substrate; and partially curing the resin by carrying out a first type of curing reaction.

With this manufacturing method, a receiving substrate having a curable resin layer can be manufactured by carrying out a process of partially curing the resin by a first type of curing reaction. This receiving substrate can prevent localized stress from being applied to the microstructure during laser lift-off, and can firmly hold the microstructure. Therefore, the manufactured receiving substrate can receive the microstructure by laser lift-off with reduced damage, and can hold the microstructure with reduced misalignment and tilt.

For example, the at least two types of curing reactions may include a combination of a photocuring reaction and a thermal curing reaction, a combination of thermal curing reactions having different curing onset temperatures, or a combination of photocuring reactions having different curing wavelengths.

The combinations of the above curing reactions are not particularly limited, but can be, for example, the combinations listed above.

In this case, for example, the at least two types of curing reactions may include a combination of at least two selected from the group consisting of a radical curing system, a cationic curing system, an anionic curing system, an addition curing system, and a condensation curing system.

The combinations of the above curing reactions are not particularly limited, but can be, for example, the combinations listed above.

The present invention also provides a lifting method for transferring a microstructure formed on a supply substrate to a receiving substrate by laser lift-off, comprising the steps of:
The surface of the microstructure facing the receiving substrate has a protrusion,
the surface of the receiving substrate onto which the microstructure is transferred has a curable resin layer;
The microstructure is pressed against the curable resin layer so that the protrusions are embedded in the curable resin layer;
the curable resin layer is cured in a state in which the protrusions are embedded in the curable resin layer, thereby holding the microstructure on the receiving substrate;
The present invention provides a lifting method in which laser lift-off is performed while the microstructure is held on the receiving substrate.

With this type of lifting method, by performing laser lift-off with the protrusions of the microstructure buried in the curable resin layer, it is possible to prevent local stress from being applied to the microstructure during laser lift-off. Therefore, with the lifting method of the present invention, even microstructures having protrusions can be transferred from a supply substrate to a receiving substrate while preventing damage. Furthermore, the curable resin layer of the receiving substrate used in the lifting method of the present invention can be hardened while holding the microstructure, thereby increasing its hardness. Therefore, with the lifting method of the present invention, the microstructure can be held on the receiving substrate while suppressing misalignment and tilt of the received microstructure.

The present invention also provides a method for holding a microstructure having a protrusion on a receiving substrate, the method comprising the steps of:
the receiving substrate has a curable resin layer on a surface for holding the microstructure;
The microstructure is pressed against the curable resin layer so that the protrusions are embedded in the curable resin layer;
The present invention provides a holding method for holding the microstructure on the receiving substrate by hardening the hardenable resin layer in a state where the protrusions are embedded in the hardenable resin layer.

With this type of holding method, the protrusions of the microstructure are embedded in the curable resin layer, and the curable resin layer is cured, allowing the microstructure to be held on the receiving substrate while minimizing damage, misalignment, and tilt of the microstructure.

The present invention also provides a method for cleaning a microstructure, comprising the steps of:
There is also provided a method for cleaning a microstructure, which comprises transferring the microstructure to the receiving substrate by the lifting method of the present invention, and then cleaning the microstructure with an acid or alkaline cleaning solution.

As described above, the lifting method of the present invention can hold the microstructure on the receiving substrate while minimizing misalignment and tilt of the received microstructure. Therefore, the cleaning method of the present invention can clean the microstructure while minimizing the falling off, misalignment, and tilt of the microstructure.

The present invention also provides a method for cleaning a microstructure having protrusions, comprising the steps of:
The microstructure is pressed against a curable resin layer so that the protrusions are embedded in the curable resin layer;
The cleaning method includes cleaning the microstructure with an acid or alkaline cleaning solution after the curable resin layer is cured, so that the protrusions of the microstructure are covered with the resin layer without any gaps and no air bubbles are present in the resin layer within 5 μm around the protrusions.

With this type of cleaning method, the protrusions of the microstructure are embedded in a curable resin layer, and after this curable resin layer is cured, the microstructure is cleaned in a state in which the protrusions of the microstructure are covered by the resin layer without any gaps and there are no air bubbles in the resin layer within 5 μm around the protrusions, thereby preventing the microstructure from falling off, shifting in position, or tilting due to cleaning.

As described above, the receiving substrate of the present invention allows the microstructure to be received by laser lift-off while minimizing damage, and also reduces misalignment and tilt of the microstructure.

Furthermore, the method for manufacturing a receiving substrate of the present invention makes it possible to receive a microstructure by laser lift-off while minimizing damage, and also makes it possible to manufacture a receiving substrate that can minimize misalignment and tilt of the microstructure.

In addition, the lifting method of the present invention can transfer microstructures having protrusions from a supply substrate to a receiving substrate while preventing damage. In addition, the lifting method of the present invention can hold the microstructure on the receiving substrate while suppressing misalignment and tilt of the received microstructure.

Furthermore, the holding method of the present invention makes it possible to hold the microstructure on the receiving substrate while suppressing positional shifts and tilts of the microstructure.

Furthermore, the cleaning method of the present invention makes it possible to clean microstructures while minimizing falling off, misalignment, and tilt.

1 is a schematic diagram showing an example of a receiving substrate of the present invention. 1A to 1C are schematic diagrams showing an example of a method for manufacturing a receiving substrate according to the present invention. FIG. 2 is a schematic diagram showing an example of a supply substrate that can be used in the present invention. FIG. 2 is a schematic diagram showing an example of a lifting method of the present invention. FIG. 2 is a schematic diagram showing lamination and secondary curing in an example of the lifting method of the present invention. FIG. 5B is a detailed view of FIG. 7 is a schematic diagram of another side of the laminated substrate shown in FIG. 6. FIG. 2 is a schematic diagram showing LLO and peeling in an example of the lifting method of the present invention. FIG. 1 is a schematic diagram showing an example of a cleaning method of the present invention. 1 is a photograph of the microstructure after transfer according to Example 1, the microstructure after peeling following this transfer, and the microstructure after cleaning following this peeling. Photographs of the microstructure after transfer according to the reference example, the microstructure after peeling following this transfer, and the microstructure after cleaning following this peeling.

As described above, there was a need to develop a receiving substrate that can receive microstructures while minimizing damage and can hold the microstructures while minimizing misalignment and tilt, a method for manufacturing such a receiving substrate, a lifting method that can transfer the microstructures from the supply substrate to the receiving substrate while minimizing damage and hold the microstructures while minimizing misalignment and tilt, a holding method that can minimize misalignment and tilt of the microstructures, and a cleaning method that can clean the microstructures while minimizing falling off, misalignment, and tilt.

After extensive research into the above-mentioned problems, the inventors discovered that by using a receiving substrate containing a curable resin layer, it is possible to receive the microstructure by laser lift-off while minimizing damage, and also to reduce misalignment and tilt of the microstructure, thus completing the present invention.

That is, the present invention provides a receiving substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off, comprising:
The surface onto which the minute structure is transferred is a receiving substrate having a curable resin layer.

The present invention also provides a method for producing a receiving substrate having a curable resin layer, the method comprising the steps of: forming a layer of a resin capable of at least two types of curing reactions on one side of a substrate for preparing a receiving substrate; and partially curing the resin by carrying out a first type of curing reaction.

The present invention also provides a lifting method for transferring a microstructure formed on a supply substrate to a receiving substrate by laser lift-off, comprising the steps of:
The surface of the microstructure facing the receiving substrate has a protrusion,
the surface of the receiving substrate onto which the microstructure is transferred has a curable resin layer;
The microstructure is pressed against the curable resin layer so that the protrusions are embedded in the curable resin layer;
the curable resin layer is cured in a state in which the protrusions are embedded in the curable resin layer, thereby holding the microstructure on the receiving substrate;
This is a lift method in which laser lift-off is performed while the microstructure is held on the receiving substrate.

The present invention also provides a method for holding a microstructure having a protrusion on a receiving substrate, comprising the steps of:
the receiving substrate has a curable resin layer on a surface for holding the microstructure;
The microstructure is pressed against the curable resin layer so that the protrusions are embedded in the curable resin layer;
This is a holding method in which the microstructure is received and held on the substrate by hardening the hardenable resin layer in a state in which the protrusions are embedded in the hardenable resin layer.

The present invention also provides a method for cleaning a microstructure, comprising the steps of:
This is a method for cleaning a microstructure, in which the microstructure is transferred to the receiving substrate by the lifting method of the present invention, and then the microstructure is cleaned with an acid or alkaline cleaning solution.

The present invention also provides a method for cleaning a microstructure having protrusions, comprising the steps of:
The microstructure is pressed against a curable resin layer so that the protrusions are embedded in the curable resin layer;
This is a cleaning method in which, after the curable resin layer is hardened, the microstructure is cleaned with an acid or alkaline cleaning solution while the protrusions of the microstructure are covered with the resin layer without any gaps and no air bubbles are present in the resin layer within 5 μm around the protrusions.

The present invention is described in detail below, but is not limited to these.

[Receiving board]
FIG. 1 shows a schematic diagram of an example of a receiving substrate of the present invention.

The receiving substrate 10 shown in Figure 1 is a receiving substrate 10 for transferring and receiving a microstructure formed on a supply substrate by laser lift-off. The supply substrate and the microstructure will be described later.

The receiving substrate 10 has a curable resin layer 12 on one surface (the surface to which the microstructure is transferred) 10A, as shown in Figure 1. The receiving substrate 10 in the example shown in Figure 1 further includes a support substrate 11 that supports the curable resin layer 12.

The curable resin layer 12 is a layer of resin that can be cured, and can be said to be in a first cured state, a B-stage state, or a semi-cured state.

The resin of such a curable resin layer 12 can deform to conform to the surface shape of the microstructure. When the curable resin layer 12 is cured (e.g., second curing), the resin of the curable resin layer 12 can be hardened and maintained while conforming to the surface shape of the microstructure, so that it is possible to prevent local stress from being applied to the microstructure even during laser lift-off (LLO) and to firmly hold the microstructure. Therefore, the receiving substrate 10 of the present invention can receive the microstructure while suppressing damage, and can also prevent misalignment and tilting.

The curable resin layer 12 and supporting substrate 11 are described in more detail below.

<Curable Resin Layer>
The resin of the curable resin layer 12 used in the present invention is not particularly limited as long as it is curable, and may be, for example, photocurable or thermosetting.

The resin of the curable resin layer 12 may be, for example, a B-stage two-stage curing resin. After receiving the microstructure, such a resin layer 12 is subjected to a secondary curing process, thereby enabling the microstructure to be held without shifting or tilting.

The B-stage resin of a two-stage curing type resin may be, for example, a two-stage curing type silicone composition that has been subjected to a primary curing.

The two-stage curing silicone composition is a silicone composition that can be cured in at least two stages by a combination of at least two types of curing reactions selected from, for example, addition curing reaction, photoradical polymerization reaction, thermal radical polymerization reaction, cationic curing reaction, anionic curing reaction, and condensation curing reaction. The curing form may be freely combined within a range that does not inhibit each other's curing reaction, but among them, it is preferable to use a combination of addition curing reaction and photoradical polymerization reaction, a combination of addition curing reaction and thermal radical polymerization reaction, and a combination of photoradical polymerization reaction and thermal radical polymerization reaction from the viewpoint of ease of resin design or curing, and a combination of addition curing reaction and photoradical polymerization reaction is particularly preferable from the viewpoint of ease of design and curing. The at least two types of curing reaction are not particularly limited as long as they are two or more, but can be, for example, two or more and four or less.

After the application step is performed on the support substrate 11, for example, when the first curing is performed by a hydrosilylation reaction, the composition is heated and cured for 5 to 90 minutes, preferably in an environment of 20 to 200° C.; when the first curing is performed by a photoradical polymerization reaction, the composition is irradiated with ultraviolet light, preferably in a nitrogen environment, with an illuminance of 50 to 3,000 mW/ ^cm2 and an integrated light amount of 100 to 20,000 mJ/ ^cm2 , using 365 nm light as an index. In this way, a first cured curable silicone-based resin layer can be formed under curing conditions suitable for the silicone-based composition.

Here, the storage modulus of the curable resin layer 12 after the first curing is desirably 10 to 1000 Pa at 25°C, and particularly preferably 100 to 500 Pa. Unlike a liquid resin layer, a resin layer having a storage modulus in the range of 10 to 1000 Pa at 25°C can easily maintain in-plane uniformity and can easily conform to the irregularities of the microstructure.

When the obtained curable resin layer 12 is second-cured, for example, when the second curing is performed by a hydrosilylation reaction, the layer is heated and cured for 5 to 90 minutes in an environment of preferably 20 to 200° C.; when the second curing is performed by a photoradical polymerization reaction, the composition is irradiated with ultraviolet light at an illuminance of 50 to 3,000 mW/cm ² and an integrated light amount of 100 to 20,000 mJ/cm ² , preferably in a nitrogen environment, using 365 nm light as an index. In this way, a second-cured resin layer (e.g., a silicone-based resin layer) can be formed under curing conditions suitable for the curable silicone-based composition.

Here, it is preferable that the curable resin layer 12 has a storage modulus at 25°C of 1 MPa to 30 GPa upon curing (secondary curing), and more preferably 4 MPa to 5 GPa. If the storage modulus at 25°C after secondary curing is 1 MPa or more, the retention force for the microstructures can be sufficiently ensured, and, for example, falling off during cleaning can be sufficiently suppressed. Furthermore, if the storage modulus at 25°C after secondary curing is 30 GPa or less, a retention force sufficient for application to the next process can be exhibited.

The curable resin layer 12 is preferably in a gel state, for example a silicone-based gel layer. A gel-like resin layer can more reliably prevent damage to the microstructure during laser lift-off. In the present invention, gel-like refers to a jelly-like state in which the liquid has lost its fluidity and has surface tackiness.

It is preferable that the curable resin layer 12 has tackiness to the microstructure. Such a resin layer can further prevent the received microstructure from shifting out of position.

It is preferable that the hardness of the curable resin layer 12 increases when cured. If the hardness of the resin layer increases when cured, the positional deviation or tilt of the microstructure can be further suppressed after curing.

Alternatively, it is also preferable that the curable resin layer 12 is one that increases its adhesive strength to the microstructure or increases its retention strength of the microstructure upon curing. Such a resin layer can further reduce the positional shift or tilt of the microstructure after curing.

Alternatively, it is also preferable that the curable resin layer 12 becomes rubber-like when cured. If the resin layer becomes rubber-like when cured, the positional deviation and tilt of the microstructure can be further suppressed after curing. In the present invention, rubber-like means a state in which the resin layer exhibits a resilience against load and impact and has excellent stretchability and elasticity.

In addition, the curable resin layer 12 may become a cured resin such as a high-hardness plastic upon curing rather than a rubber-like material.

<Support substrate>
Examples of the support substrate 11 used in the receiving substrate 10 include a synthetic quartz glass substrate and float glass, with a synthetic quartz glass substrate being particularly preferred from the standpoints of flatness and transparency.

In addition, the size of the support substrate 11 used for the receiving substrate 10 is preferably the same as or larger than the diameter of the supply substrate (described in detail below) used. Specifically, when a sapphire substrate with an outer diameter of 10.16 cm (4 inches) is used as the supply substrate, a receiving substrate 10 with an outer diameter of 10.16 to 20.32 cm (4 to 8 inches) can be used.

In order to reliably transfer some or all of the multiple microstructures from the supply substrate to the receiving substrate 10, it is preferable that when the multiple microstructures formed on one side of the supply substrate are bonded to the receiving substrate 10 having a curable resin layer 12 on a support substrate 11, each microstructure is temporarily and uniformly fixed to the curable resin layer 12 of the receiving substrate 10.

In order to temporarily fix the microstructures with such precision, it is preferable that the support substrate 11 used for the receiving substrate 10 has a power spectral density of ¹⁰¹² nm4 or ^less at spatial frequencies of 1 mm ^-1 or more, as measured by a white light interferometer with a pixel count of 1240 x 1240 over an area of 6.01 mm x 6.01 mm, and in particular, when the microstructures are micro LEDs, taking into account the distance between the microstructures, it is preferable that the power spectral density of 10 mm ^-1 or more and 50 mm ^-1 or less, as measured by a white light interferometer with a pixel count of 1240 x 1240 over an area of 6.01 mm x 6.01 mm, is ¹⁰⁹ nm4 or ^less , taking into account the distance between the microstructures.

In addition, since the receiving substrate 10 is used to temporarily fix the microstructure with high precision, it is preferable that the support substrate 11 used for the receiving substrate 10 has a small thickness variation. For example, the thickness variation (TTV) measured by a wavelength conversion Fizeau type flatness tester manufactured by Mizojiri Optical Industries Co., Ltd. is preferably 2 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less.

In addition, the microstructure to be held by the receiving substrate 10 of the present invention may be a microstructure having protrusions or a microstructure without protrusions.

[Method of manufacturing the receiving substrate]
The receiving substrate of the present invention can be manufactured, for example, by the method for manufacturing a receiving substrate of the present invention, which will be described below with reference to Fig. 2. However, the receiving substrate of the present invention can also be manufactured by a method other than the method for manufacturing a receiving substrate of the present invention, which will be described below.

First, as shown in Figure 2 (A), prepare a substrate (support substrate) 11 for preparing a receiving substrate. For details of the support substrate to be used, please refer to the previous explanation.

Next, as shown in FIG. 2(B), a process is performed to form a layer 12a of a resin capable of at least two types of curing reactions on one side of the support substrate 11, thereby obtaining a composite 10a.

This process may include, for example, coating the support substrate 11 with at least two types of resin capable of curing reactions.

The resin used here is not particularly limited as long as it is capable of undergoing at least two types of curing reactions. For example, the two-stage curing silicone composition described above can be used.

When the two-stage curing silicone composition shown above is used as a resin capable of at least two types of curing reactions, the coating on the support substrate 11 may be performed by applying the two-stage curing silicone composition in any shape using spin coating, slit coating, screen printing, or the like. The thickness of the coating of the two-stage curing silicone composition may be determined arbitrarily in consideration of the shape and thickness of the microstructure to be transferred, but is preferably 1 to 500 μm, more preferably 5 to 200 μm, and even more preferably 10 to 100 μm from the viewpoint of ease of application and maintaining uniformity of the film thickness after curing. In addition, a support substrate 11 that has been previously treated with a primer may be used to improve the adhesion or adhesion at the interface between the support substrate 11 and the curable silicone resin 12a.

Next, a first type of curing reaction (so-called primary curing) is carried out to partially cure the resin capable of at least two types of curing reactions in the resin layer 12a. This causes the resin layer 12a to undergo primary curing, becoming a curable resin layer 12. As a result, the receiving substrate 10 of the present invention shown in Figure 2(C) can be obtained.

The curable resin layer 12 can be subjected to a secondary curing. The curable resin layer 12 can become the second cured resin layer 12b shown in FIG. 2(D) by the secondary curing. That is, the receiving substrate 10b shown in FIG. 2(D) has a supporting substrate 11 and a second cured resin layer 12b formed on the supporting substrate 11.

The at least two types of curing reactions described above (e.g., primary curing and secondary curing) may include, for example, a combination of a photocuring reaction and a thermal curing reaction, a combination of thermal curing reactions having different curing onset temperatures, or a combination of photocuring reactions having different curing wavelengths.

In another aspect, the at least two types of curing reactions described above (e.g., primary and secondary curing) may include, for example, a combination of at least two selected from the group consisting of a radical curing system, a cationic curing system, an anionic curing system, an addition curing system, and a condensation curing system.

[Lifting method]
The lifting method of the present invention is a lifting method for transferring a microstructure formed on a supply substrate to a receiving substrate by laser lift-off. An example of the lifting method of the present invention will be described with reference to FIGS.

The receiving substrate 10 of the present invention described above can be used as the receiving substrate used in the lifting method of the present invention.

The supply substrate that can be used in the present invention is, for example, a supply substrate 20 having a plurality of microstructures 100 formed on one surface of a support substrate 21, as shown in FIG. 3, and having protrusions 130 on a surface 100A of the microstructure 100 facing the receiving substrate 10. In FIG. 3, protrusions 130 such as bumps are formed on the element body 120 of the microstructure 100. Recesses 110 are formed between the protrusions 130. By using the receiving substrate of the present invention described above, it is also possible to transfer a microstructure without protrusions by laser lift-off.

Examples of the support substrate 21 used in the supply substrate 20 include a sapphire substrate, a GaAs substrate (gallium arsenide substrate), a Si substrate, a SiC substrate, etc., and the diameter is arbitrary.

Examples of the microstructure 100 include elements obtained by forming a basic structure as a device on a support substrate 21 through processes carried out in typical semiconductor pre-processing steps, such as epitaxial growth, ion implantation, wet etching, dry etching, vapor deposition, and electrode formation, and then separating the elements using standard methods, such as blade dicing, dry etching, and laser dicing, to a depth required for separating the elements.

For example, if the microstructure is an LED, an LED epitaxial substrate is prepared on a 10.16 cm (4 inch) sapphire substrate, with a buffer layer, a 3 μm N-type GaN layer, a known light emitting layer structure, and an epitaxial layer with P-type GaN stacked for a total thickness of 4 μm. After that, the N-layer is locally exposed by dry etching, and a P-type electrode is formed on the P-layer by a known process, an N-type electrode is formed in contact with the exposed N-layer, and a bump is formed on the electrode by a method such as plating, vapor deposition, or sputtering. Then, in order to separate LED elements of a predetermined size, laser dicing is performed so that at least the sapphire substrate is reached and the elements are completely separated, and the microstructure is obtained.

The size of the microstructure 100 is arbitrary, but for example, in the case of a power LED, it is about 1 mm square. In addition, in the case of an LED element, it is about 300 μm square, in the case of a mini LED, it is about 100 μm square, in the case of a micro LED, it is about 60 μm square or less, and in the case of a very small micro LED, it is 30 μm square or less.

Although the shape of the microstructure 100 described above is an example of a roughly square shape, the present invention is not limited to this. For example, in the case of a micro LED, it may be a rectangle with one side measuring 30 to 60 μm and the other side measuring 10 to 30 μm.

In addition, the thickness of the microstructure 100 depends on the epitaxial growth thickness on the support substrate 21 and is not particularly limited, but is preferably approximately 3 to 10 μm.

Now, in the lifting method of this example, the receiving substrate 10 and the supply substrate 20 are aligned with each other so that the surface 10A of the curable resin layer 12 of the receiving substrate 10 onto which the microstructure 100 is transferred faces the protrusion 130 provided on the surface 100A of the microstructure 100 of the supply substrate 20, as shown in, for example, Figure 4 (A).

Next, as shown in FIG. 4B, the microstructure 100 is pressed against the curable resin layer 12 so that the protrusions 130 are embedded in the curable resin layer 12, thereby obtaining the laminated substrate 30. This process can also be called lamination.

Next, as shown in FIG. 4(C), the curable resin layer 12 is cured while the protrusions 130 are embedded in the curable resin layer 12, thereby holding the microstructure 100 on the receiving substrate 10. This process can also be called the second curing.

In another example, the bonding of the multiple microstructures 100 formed on one side of the supply substrate 20 to the curable resin layer (e.g., a silicone-based resin layer) 12 on the receiving substrate 10 and the second curing can be performed, for example, as shown in Figure 5. Note that in Figure 5, the protrusions of the microstructures 100 are omitted.

In this example, after being aligned as shown in Figure 5 (A), the receiving substrate 10 and the supply substrate 20 are bonded together under pressure so that the microstructure 100 on the supply substrate 20 and the curable resin layer 12 on the receiving substrate 10 face each other, as shown in Figure 5 (B), to obtain a laminate 30.

Thereafter, as shown in FIG. 5(C), a second curing of the curable resin layer 12 is performed, and the resin layer 12b after the second curing is hardened to obtain a laminated substrate 40.

Figures 6 and 7 show details of Figure 5 (C). Figure 7 is a schematic diagram of the microstructure 100 observed through the support substrate 11 of the laminated substrate 40 in the state of Figure 6. The microstructure 100 to be transferred by the lifting method of the present invention has protrusions 130 as described above. In Figures 6 and 7, the protrusions 130 such as bumps are covered without any gaps by the secondary cured resin layer 12b. Therefore, the recesses 110 of the microstructure 100 shown in Figure 3 are filled with the resin layer 12b.

If no air bubbles exist within the resin layer 12b within 5 μm around the protrusion 130, it is possible to prevent the protrusion 130 from coming into contact with the cleaning solution in the cleaning process, and to prevent changes in the components that make up the protrusion 130. The absence of air bubbles within the resin layer 12b within a range of 5 μm from the protrusion 130 can be confirmed using, for example, a laser microscope.

It is preferable to apply pressure during lamination so that no air bubbles remain between the curable resin layer 12 and the microstructure 100. For example, it is preferable to perform lamination by applying a load of preferably 0.05 to 1.0 MPa, more preferably 0.10 to 0.5 MPa. At this time, pressure may be applied under reduced pressure so that the curable resin layer 12 can easily follow the shape of the microstructure. Furthermore, if the second curing of the curable resin is caused by heating, heating may be performed simultaneously with lamination to cause the second curing.

The second curing of the curable resin layer 12 is preferably performed by placing the composition in a heating furnace for 5 to 90 minutes in an environment of 80 to 200° C. when the second curing is performed by a hydrosilylation reaction, or by irradiating the composition with ultraviolet light at an illuminance of 50 to 3,000 mW/ ^cm2 and an accumulated light amount of 100 to 20,000 mJ/ ^cm2 , preferably in a nitrogen environment, using 365 nm light as an index, to form a second-cured resin layer 12b under curing conditions suitable for the curable silicone-based resin used.

Next, as shown in Figures 4(D) and 8(A) (protrusions of the microstructure 100 are omitted), laser lift-off is performed using laser light L while the microstructure 100 is held on the receiving substrate 10. Laser lift-off performed in this state can also be called contact laser lift-off (CLLO).

More specifically, the laminated substrate 40 obtained in the lamination and secondary curing process is irradiated with pulsed laser light L, for example from the surface of the supply substrate 20 opposite to the surface on which the microstructure 100 is formed, to peel off the microstructure 100 from the support substrate 21. This allows the transfer of the microstructure 100 from the supply substrate 20 to the second cured resin layer 12b on the receiving substrate 10.

In the LLO process, for example, when the microstructure 100 is a gallium nitride microstructure fixed to a support substrate 21 of a supply substrate 20 such as a sapphire substrate, the gallium nitride in the irradiated portion is melted by irradiation with laser light such as an excimer laser or a YAG laser, thereby allowing the gallium nitride microstructure 100 to be peeled off from the supply substrate 20. In this case, it is preferable to use KrF excimer laser light, particularly for microLEDs, from the viewpoint of the reliability of the microstructure 100.

Specifically, laser light is selectively irradiated to cause laser ablation at the interface between the microstructure 100 to be selected and the support substrate 21 of the supply substrate 20. As a result, in the case of a gallium nitride microstructure, for example, gallium nitride decomposes into metallic gallium and nitrogen between the microstructure 100 to be selected and the support substrate 21 of the supply substrate 20, generating gas, so that the microstructure 100 can be peeled off relatively easily.

After irradiating all the microstructures 100 to be transferred in the same manner with the laser light L, the receiving substrate 10b on which the microstructures 100 have been transferred can be peeled off from the support substrate 21 of the supply substrate 20, as shown in Fig. 4(E) and Fig. 8(B) (the protrusions of the microstructures 100 are omitted). This makes it possible to obtain the receiving substrate 10c holding the microstructures 100.

Because the supply substrate 20 and the microstructure 100 are separated by the LLO process, the supply substrate 20 can be easily peeled off using an appropriate jig.

In the lifting method of the present invention described above, by performing laser lift-off with the protrusions 130 of the microstructure 100 buried in the curable resin layer 12, it is possible to prevent local stress from being applied to the microstructure 100 during laser lift-off. Therefore, in the lifting method of the present invention, even with respect to the microstructure 100 having the protrusions 130, it is possible to transfer it from the supply substrate to the receiving substrate while preventing damage. In addition, the curable resin layer 12 of the receiving substrate 10 used in the lifting method of the present invention can be cured and hardened while holding the microstructure 100. Therefore, in the lifting method of the present invention, the received microstructure 100 can be held on the receiving substrate 10 while suppressing positional deviation and tilt.

The receiving substrate 10c may be used in the next process as is, or may be subjected to a cleaning process using an acid or alkaline cleaning solution as described below, or a surface cleaning process using oxygen plasma or argon plasma, etc., before being used in the next process.

The microstructure 100 transferred onto the receiving substrate 10c via the lifting method of the present invention, or further via the cleaning method described below, can be mounted on a circuit board via a desired process, such as using a transfer stamp material described in Patent Document 1, or transferring the microstructure 100 again onto a polyimide layer. In other words, the receiving substrate 10c can also be used as a supply substrate (donor substrate) that supplies the microstructure 100 to another substrate in another process.

[Holding method]
The bonding and secondary curing shown in Figures 4(B), 4(C) and 5 can also be called the holding method of the present invention. That is, the holding method of the present invention for holding the microstructure 100 having the protrusions 130 on the receiving substrate 10 is a holding method in which the receiving substrate 10 has a curable resin layer 12 on the surface holding the microstructure 100, the microstructure 100 is pressed against the curable resin layer 12 to make the protrusions 130 embedded in the curable resin layer 12, and the curable resin layer 12 is cured in the state in which the protrusions 130 are embedded in the curable resin layer 12, thereby holding the microstructure 100 on the receiving substrate 10.

With this type of holding method, the protrusions 130 of the microstructure 100 are embedded in the curable resin layer 12, and the curable resin layer 12 is cured, thereby making it possible to hold the microstructure 100 on the receiving substrate 10 while minimizing damage, misalignment, and tilt of the microstructure 100.

In addition, with the receiving substrate of the present invention described above, even in the case of a microstructure having no protrusions, the contact surface of the microstructure can be pressed into the curable resin layer and the curable resin layer can be secondary cured to retain the microstructure having no protrusions on the receiving substrate of the present invention.

[Cleaning method]
In one aspect of the cleaning method of the present invention, after the microstructure 100 is received and transferred to the substrate 10 by the lift-off method of the present invention described above, the microstructure 100 is cleaned with an acid or alkaline cleaning solution.

In another aspect, the cleaning method of the present invention is a cleaning method for a microstructure 100 having protrusions 130, for example as shown in Figure 3, in which the microstructure 100 is pressed against a curable resin layer 12, for example as shown in Figure 5 (B), so that the protrusions 130 are embedded in the curable resin layer 12, and after the curable resin layer 12 is cured, for example as shown in Figures 6 and 7, the protrusions 130 of the microstructure are covered tightly by the resin layer 12b, and no air bubbles are present in the resin layer 12b within 5 μm around the protrusions 130, and the microstructure 100 is cleaned with an acid or alkaline cleaning solution.

The cleaning method of the present invention is described in more detail below.

Figure 9 shows an example of the cleaning method of the present invention, and shows a schematic diagram of the process of cleaning metal Ga after the LLO process is completed and peeling is performed as shown in Figure 8.

In FIG. 9A, the second cured resin layer 12b holding the microstructure 100 is present on the receiving substrate 10c after the LLO process, and a metal (e.g., Ga) 140 is attached to the surface of the microstructure 100 opposite to the resin layer 12b. Here, the interface between the resin layer 12b and the microstructure 100 is in a state of close contact, so that in this state, the receiving substrate 10 is immersed entirely in an acid or alkaline cleaning solution or washed away, as shown in FIG. 9B, and the metal 140 is dissolved and removed, and a receiving substrate 10d holding the transferred microstructure is obtained. At this time, the interface of the microstructure 100 on the resin layer 12b side is covered and held by the resin layer 12b, so it is not affected by the acid or alkaline cleaning solution and is not removed by the cleaning process. The receiving substrate 10d is further washed thoroughly with pure water and dried by air drying or the like, and is used in the next process.

In these cleaning steps, the microstructure 100 is held by the resin layer 12b and remains without falling off the surface of the resin layer 12b. Furthermore, because the microstructure 100 is held by the resin layer 12b, it is possible to suppress positional deviation and tilt.

In particular, in the example shown in Figure 9, the entire protrusion 130 of the microstructure 100 is covered with the resin layer 12b without any gaps, and there are no air bubbles within the resin layer 12b within 5 μm around the protrusion 130, so that the protrusion 130 can be prevented from being affected by acid or alkali during the cleaning process.

Furthermore, there is no air layer of up to 1 μm or more at the interface between the resin layer 12b and the element body 120 and the protrusion 130, and by subjecting them to the cleaning process in a state of close contact with each other, it is possible to prevent the composition of the interface of the element body 120 on the resin layer 12b side, and, if the protrusion 130 is a bump, the composition of the bump from being affected, and the element can be used in the next process without any problems.

In the case of an acid cleaning solution, the cleaning solution used in this cleaning process can be a mixture of concentrated hydrochloric acid, concentrated nitric acid, concentrated sulfuric acid, etc., mixed uniformly with pure water in any ratio, and multiple aqueous acids can also be used. In this case, the pH of the cleaning solution is preferably 0 to 4.0. A pH within this range allows for sufficient solubility of the metal (e.g. Ga) 140.

In addition, in the case of an alkaline cleaning solution, sodium hydroxide, potassium hydroxide, ammonium hydroxide, magnesium hydroxide, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, sodium carbonate, sodium bicarbonate, and potassium acetate dissolved in pure water at any concentration can be used, and multiple alkaline cleaning solutions can be used. In this case, the pH of the cleaning solution is preferably 9.5 to 14.0, and a pH within this range allows for sufficient solubility of the metal (e.g., Ga) 140.

As explained above, the receiving substrate of the present invention can also hold microstructures that do not have protrusions. Therefore, in a modified version of the cleaning method of the present invention, a microstructure that does not have protrusions can also be cleaned while being held by the receiving substrate of the present invention.

The present invention described above can be applied to the manufacturing process of LED displays, particularly for signage, TV, medical, automotive, smartphones, etc.

The present invention will be explained in detail below using examples and comparative examples, but the present invention is not limited to these.

Supply substrates having the following microstructures were prepared.
<Supply Substrate A and Microstructure A>
A sapphire substrate with a size of 90×140 μm, a total thickness of 19 μm, a mini LED element with a bump height of 7 μm, and cut into a 1.5 cm square. <Supply substrate B and microstructure B>
A sapphire substrate cut into 1.5 cm squares, with a size of 18 x 36 μm, total thickness of 9 μm, and a micro LED element with a bump height of 4 μm.

In addition, the following was prepared as a support substrate for the receiving substrate.
<Support substrate used for receiving substrate>
A synthetic quartz substrate with an outer diameter of 15.24 cm (6 inches), a thickness of 1 mm, and a total thickness variation (TTV) of 0.8 μm.

<Experimental Contents: Examples 1 to 5>
[Preparation of receiving substrate]
3 g of the following two-stage curing silicone resin composition (Silicone A or B) was dropped onto a supporting substrate, and the composition was uniformly coated on the supporting substrate to a film thickness of 30 μm using a spin coater. The resulting coating was subjected to the following first curing conditions to primarily cure the silicone resin composition into a gel state, thereby producing a receiving substrate having a curable silicone resin.

[Stitching]
The supply substrate and the receiving substrate were bonded together under pressure of 0.5 MPa so that the microstructures on the supply substrate and the curable silicone resin on the receiving substrate, respectively, shown in Table 1 below, were in contact with each other. The curable silicone resin was then subjected to secondary curing under the conditions shown below. A laser microscope was then used to check whether there was an air layer of up to 1 μm or more between the supply substrate and the microstructure and the secondary cured silicone resin, and whether there were any air bubbles in the resin within 5 μm around the protrusions.

[LLO and Peeling]
Next, the microstructure was irradiated with KrF excimer laser light from the rear surface of the supply substrate to perform LLO, after which the supply substrate was peeled off from the receiving substrate.

After peeling, the transfer rate and damage rate of the microstructures from the supply substrate to the receiving substrate were evaluated. The results are shown in Table 1 below.

Thereafter, the surface of the microstructure was cleaned by immersing it for 3 minutes in an acid or alkaline cleaning solution as described below and shown in Table 1. Next, the process of cleaning by immersing it in pure water for 3 minutes was repeated twice, and the structure was air-dried.

After air drying, the microstructures were checked for tilt and falling off. The results are shown below.

Acidic cleaning solution: 12% by weight hydrochloric acid aqueous solution Alkaline cleaning solution: 5% by weight potassium hydroxide aqueous solution

[Measurement of Elastic Modulus]
The dynamic viscoelastic properties of the silicone gel cured product in the present invention are defined by the storage modulus G' at a specific frequency and a specific temperature, and the measurements were performed using a viscoelasticity measuring device ARES G-II manufactured by TA Instruments. A silicone resin cured and molded to a size of 3 cm square and 500 μm thick was sandwiched between the circular measuring part of the testing device and a parallel plate with a diameter of 20 mm so as not to trap air bubbles, and the strain value was measured for 10 minutes at a condition of 4% and a frequency of 1 Hz while maintaining a temperature of 25°C. The value 10 minutes after the start of the measurement was read as the storage modulus G'. The silicone resin after the second curing was also measured using the same procedure and conditions. The results are shown below.

Silicone A: A two-stage curing silicone composition that undergoes a first curing by an addition reaction under an environment of 120°C x 1 h, becoming a gel with a storage modulus G' of 0.2 kPa, and then undergoes a second curing by a photoradical reaction under nitrogen with 365 nm UV-LED 3000 mJ/cm ² (illuminance: 100 mW/cm ² ) to become a rubber with a storage modulus G' of 8.2 MPa.

Silicone B: A two-stage curing type silicone composition which is first cured by a photoradical reaction caused by irradiation with a 365 nm UV-LED of 3000 mJ/cm ² (illuminance: 100 mW/cm ² ) under nitrogen to become a gel with a storage modulus G' of 5 kPa, and then secondly cured by an addition reaction at 120°C for 1 h to become a rubber with a storage modulus G' of 4 GPa.

<Experimental Contents: Comparative Examples 1 to 4>
The transfer rate, breakage rate, and positional deviation of the microstructure in the LLO process, as well as the inclination and falling off of the microstructure in the cleaning process, were confirmed by the same process as in the Examples, except that the receiving substrate was prepared by curing the silicone composition (silicone C) shown below into a rubber-like state under a single curing condition only. That is, the receiving substrate used in Comparative Examples 1 to 4 did not have a curable resin layer.

The elastic modulus of the rubber-like cured silicone C was measured using the procedure described above.

Silicone C: A heat-curing silicone composition that hardens by addition reaction in an environment of 120°C x 1h, becoming rubber-like with a storage modulus G' of 4.7 MPa.

Figure 10 also shows photographs of the microstructure after transfer by LLO in Example 1 (Figure 10(A)), the microstructure after peeling following this transfer (Figure 10(B)), and the microstructure after cleaning following this peeling (Figure 10(C)).

The appearance of the microstructure after transfer by LLO in each of Examples 2 to 5, the microstructure after peeling following this transfer, and the microstructure after cleaning following this peeling were similar to those shown in Figures 10 (A), 10 (B), and 10 (C).

As is clear from the results shown in Table 1 above and Figure 10, in Examples 1 to 5, microstructures having protrusions were able to be transferred from a supply substrate to a receiving substrate with a transfer rate of 99% or more, without damage or misalignment.

Furthermore, as is clear from the results shown in Table 1 above and Figure 10, in Examples 1 to 5, no falling off or tilting of the microstructures was observed after cleaning.

These results are due to the fact that in Examples 1 to 5, the primarily cured silicone-based resin layer received the microstructure with its protrusions embedded in the primarily cured silicone-based resin layer, and the silicone-based resin layer was then secondarily cured in this state to increase its hardness, which enabled the secondarily cured silicone-based resin layer to adequately hold the microstructure, thereby preventing damage, falling off, misalignment and tilting of the microstructure during the transfer, peeling and cleaning processes using the LLO.

On the other hand, in Comparative Examples 1 to 4, a hardened rubber-like material was used, and a receiving substrate having a hardenable resin layer was not used, so the breakage rate was 5% or more. In addition, in Comparative Examples 1 and 2, positional deviation of the microstructure was also confirmed. Furthermore, as is clear from the results shown in Table 1, inclination of the microstructure was observed after cleaning in Comparative Examples 1 to 4.

Furthermore, as a reference example, LLO, peeling, and cleaning were performed in the same manner as in Example 1, except that secondary curing of the curable resin layer was not performed during LLO. Figure 11 shows photographs of the microstructure after transfer by LLO in the reference example (Figure 11(A)), the microstructure after peeling following this transfer (Figure 11(B)), and the microstructure after cleaning following this peeling (Figure 11(C)).

In the reference example, the microstructures were misaligned during LLO and the transfer rate was low. Furthermore, in the reference example, the microstructures that were not placed on the silicone-based resin layer that was secondary cured during LLO were cracked.

In addition, in the reference example, as is clear from Figures 11 (B) and 11 (C), the microstructures were observed to fall off, shift in position, and become tilted due to peeling and cleaning.

The present specification includes the following aspects.
[1] A receiving substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off, the receiving substrate having a curable resin layer on the surface onto which the microstructure is transferred.
[2] The receiving substrate according to [1], wherein the curable resin layer is photocurable or thermocurable.
[3] The receiving substrate according to [1] or [2], wherein the curable resin layer is in a B-stage state.
[4] The receiving substrate according to any one of [1] to [3], wherein the curable resin layer is in a gel state.
[5] The receiving substrate according to any one of [1] to [4], wherein the curable resin layer is a silicone-based gel layer.
[6] The receiving substrate according to any one of [1] to [5], wherein the curable resin layer has tackiness to the minute structure.
[7] The receiving substrate according to any one of [1] to [6], wherein the hardness of the curable resin layer increases upon curing.
[8] A receiving substrate according to any one of [1] to [7], wherein the curable resin layer increases its adhesive strength to the microstructure or increases its holding strength for the microstructure upon curing.
[9] The receiving substrate according to any one of [1] to [8], wherein the curable resin layer becomes rubber-like when cured.
[10] The receiving substrate according to any one of [1] to [9], wherein the storage modulus of the curable resin layer is 10 to 1000 Pa at 25° C. and becomes 1 MPa to 30 GPa upon curing.
[11] A method for manufacturing a receiving substrate having a curable resin layer, comprising the steps of forming a layer of a resin capable of at least two types of curing reactions on one side of a substrate for preparing a receiving substrate, and partially curing the resin by carrying out a first type of curing reaction.
[12] The method for manufacturing a receiving substrate described in [11], wherein the at least two types of curing reactions include a combination of a photocuring reaction and a thermal curing reaction, a combination of thermal curing reactions having different curing initiation temperatures, or a combination of photocuring reactions having different curing wavelengths.
[13] The method for producing a receiving substrate according to [11] or [12], wherein the at least two types of curing reactions include a combination of at least two selected from the group consisting of a radical curing system, a cationic curing system, an anionic curing system, an addition curing system, and a condensation curing system.
[14] A lifting method for transferring a microstructure formed on a supply substrate to a receiving substrate by laser lift-off, wherein the surface of the microstructure facing the receiving substrate has a protrusion, and the surface of the receiving substrate to which the microstructure is transferred has a curable resin layer, the microstructure is pressed against the curable resin layer so as to embed the protrusion in the curable resin layer, the curable resin layer is hardened while the protrusion is embedded in the curable resin layer, thereby holding the microstructure on the receiving substrate, and laser lift-off is performed while the microstructure is held on the receiving substrate.
[15] A holding method for holding a microstructure having protrusions on a receiving substrate, the receiving substrate having a curable resin layer on a surface for holding the microstructure, the microstructure being pressed against the curable resin layer so as to embed the protrusions in the curable resin layer, and the curable resin layer being hardened in a state in which the protrusions are embedded in the curable resin layer, thereby holding the microstructure on the receiving substrate.
[16] A method for cleaning a microstructure, comprising transferring the microstructure to the receiving substrate by the lifting method described in [14], and then cleaning the microstructure with an acid or alkaline cleaning solution.
[17] A method for cleaning a microstructure having protrusions, comprising pressing the microstructure against a curable resin layer so that the protrusions are embedded in the curable resin layer, and after the curable resin layer is cured, cleaning the microstructure with an acid or alkaline cleaning solution in a state in which the protrusions of the microstructure are covered by the resin layer without any gaps and no air bubbles are present in the resin layer within 5 μm around the protrusions.

The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included within the technical scope of the present invention.

Claims (13)

A receiving substrate for transferring and receiving a microstructure formed on a supply substrate by laser lift-off,
A curable resin layer is provided on the surface onto which the microstructure is transferred,
the curable resin layer is in a gel state,
The curable resin layer is a receiving substrate that becomes rubber-like when cured . A receiving substrate for lifting and receiving a microstructure provided on a substrate by a laser,
A curable resin layer is provided on the surface onto which the microstructure is transferred,
the curable resin layer is in a gel state,
The curable resin layer is a receiving substrate that becomes rubber-like when cured. 3. The receiving substrate according to claim 1, wherein the curable resin layer is photocurable or thermocurable. 3. The receiving substrate according to claim 1, wherein the curable resin layer is in a B-stage. 3. The receiving substrate according to claim 1, wherein the curable resin layer is a silicone-based gel layer. 3. The receiving substrate according to claim 1, wherein the curable resin layer has tackiness to the minute structure. 3. The receiving substrate according to claim 1, wherein the hardening resin layer is increased in hardness by hardening. 3. The receiving substrate according to claim 1, wherein the curable resin layer is one that, upon curing, increases its adhesive strength to the microstructure or increases its holding strength for the microstructure. 3. The receiving substrate according to claim 1, wherein the storage modulus of said curable resin layer is 10 to 1000 Pa at 25° C. and is changed to 1 MPa to 30 GPa upon curing. 2. A laser lift-off method for transferring a microstructure formed on a supply substrate to a receiving substrate according to claim 1 by laser lift-off, comprising the steps of:
The gel-like curable resin is cured to a rubber-like state, thereby holding the microstructure on the receiving substrate;
A laser lift-off method in which the microstructure is transferred by laser lift-off while being held on the receiving substrate. A lifting method for transferring a microstructure provided on a substrate to a receiving substrate according to claim 2 by a laser, comprising the steps of:
The gel-like curable resin is cured to a rubber-like state, thereby holding the microstructure on the receiving substrate;
A lifting method in which the minute structure is transferred by a laser while being held on the receiving substrate. A method for holding a microstructure on a receiving substrate according to claim 1 or 2, comprising the steps of:
The method includes: curing the gel-like hardening resin into a rubber-like state to hold the microstructure on the receiving substrate. A method for cleaning a microstructure held on a receiving substrate according to claim 1 or 2, comprising the steps of:
The gel-like curable resin is cured to a rubber-like state, thereby holding the microstructure on the receiving substrate;
A cleaning method for cleaning the minute structure with an acid or alkaline cleaning solution.

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